Manufacture of electric heaters



Patented June 7, 1 949 2,472,145 MANUFACTURE OF ELECTRIC HEATERS Charles W. Cappell, Alliso Edwin L. Wiegand 11 Park, Pa., assignor to mpany, Pittsburgh, Pa.,

a corporation of Pennsylvania Application December 5, 1945, Serial No. 632,923

14 Claims.

This invention relates to the manufacture of electric heaters, and more particularly to the manufacture of electric heating elements comprising a resistor disposed within and insulated from a tubular metallic sheath. The principal object of the invention is the provision of new and improved apparatus for use in making electric heaters, and more particularly the provision of new and improved apparatus and new and improved resistor terminals used in introducing In the drawing accompanying this specification, and forming a part of this application, there is shown, for purposes of illustration, one form which the invention may assume, and in this drawing:

Figure 1 is a vertical sectional broken view of an uppermost portion of apparatus embodying the invention,

Figure 2 is a vertical sectional broken view of a lowermost portion of the apparatus of Figure 1,

Figure 3 is a vertical sectional fragmentary means and of the embodiment shown in Figure 1,

Figure 4 is a section taken on the line 4-4 of Figure 3,

Figure 5 is a section taken on the line 55 of Figure 3, and

Figure 6 is a fragmentary view showing the positioning means and terminal means partly assembled (or disassembled), the positioning means, but not the terminal means, being turned 90 from the position shown in Figure 3.

Referring to Figures 1 and 2, a tubular metallic sheath ID has its lower end supported and positioned in any suitable way, in this instance by a support member ll having a cylindrical upper end portion providing a plug I2 insertable in the lower end of the sheath. The support member H has an enlarged portion l3 providing a shoulder [4 against which the end of the sheath in abuts when the plug [2 is in the end of the sheath. The support member ll may itself b supported and suitable way, in this instance by a base l5 having an upstanding l6 fitting in a recess H in the support member I I.

The upper end of the sheath positioned by a funnel member l8 having a bore l 9 in which the end of the sheath may be slidably .nserted against a shoulder 20 terminating the ore I 9. Communicating with the bore l9 and I0 is held and concentric therewith is a smaller bore 2| having the same diameter as the inside of the sheath l0, so that the smaller bore 2| forms an upward continuation of the inside surface of the sheath. The smaller bore 2| communicates with a downwardly tapering conical recess 22 in the funnel member I8, this recess being here shown as joining an inverted conical recess 23 communicating with a cylindrical opening 24.

A resistor 25, here shown as of helical form, is disposed in the sheath H]. The upper end portion 25a of the resistor 25 has a terminal 26 fastened thereto. The terminal 26 is made of a relatively stiff wire or rod, desirably of circular may be screwed into the helical resistor 25. The resistor may be brazed the threaded end of the positioning means 30.

The positioning means carried by a rod 32 which may be supported in 3! is conveniently carried by the rod 32 by drivefitting an internally threaded bushing 34 into the upper end of the sleeve 3|, and providing th rod with threads cooperating with the internal threads in the bushing 34.

The lower end of the resistor 25 (broken away in Figure 2) is provided with a terminal 35, having a threaded end fastened to the lower end portion of the resistor in the same manner as set forth in connection with the upper terminal 26. The shank 35a of the terminal 35 is of the same cross-section throughout, circular in this instance. The lower end of the terminal 35 is insertable in a hole 36 in the support II, and

hole by a set screw 31 extending through the portion l3. The hole 36 is desirably of such depth that the terminal 35 projects a desired distanc beyond the lower end of the sheath l0.

Disposed about the sleeve 3| and freely slid-able thereon is a tube 38 of such length that when filling of the sheath [0 with comminuted insulating material is started, the lower end of the tube 38 is long enough to reach the plug |2 while the upper end of the tube is a desired amount above the level of the opening 24. The diameter of the sleeve 3| and the outside diameter of the tube 38 are such that the outer surfac of the tube 38 is spaced a desired distance from the inside of the sheath ID, the sleeve 3| positioning the upper end of the tube 38 concentric with the sheath Ill. The lower end of the tube 38 is positioned concentric with the sheath if! by a plurality of circumferentially spaced, longitudinally extending ribs or splines 39 which may be provided on the lower end of the tube 38. In this instance the splines are on a thickened portion 88 of the tube 38, the portion 48 having a bore 41, within which the helical resistor .25 is disposed, and of such diameter that the inside surface of the bore M is freely movable longitudinally with respect to the resistor. The splines 38 slidably engage the inside wall of the sheath l0.

Referring now more particularly to Figures 3 through 6. The terminal 26 is provided with circumferentially spaced lateral projections 45, in this instance two, 180 apart. The projections 85 may be in the nature of splines, extending longitudinally a desired distance and in this instance they extend from a place near the upper end of the terminal 26 to the upper end of the terminal. The outermost surface of each lateral projection 45 desirably has'longitudinally tapering portions 45 (see also Figure 4), tapering inwardly to'a junction with the surface of the shank 21. The upper ends of the lateral projections 45 desirably also have inwardly tapering portions ll. As here shown, the lateral projections 45 are of arcuate cross-section, as seen in Figure 4. The lateral projections 45 may be formed by sidepressing the initially circular cross-section shank 21, or the projections may be provided in any other suitable way.

The sleeve 3| is constructed and arranged to cooperate with the terminal 26, as follows. The sleeve 3| has an open cylindrical bore 48 at its lower end, of sufficiently large diameter to freely receive the shank 21b t not large enough to permit passage of the upper end of the terminal with its lateral projections 45. The sleeve 3| has a larger bore 49 spaced from the lower end of the sleeve and providing, a shoulder 58 at the junction between the bores. The larger bore |9 is of sufficient diameter to freely receive the upper end of the terminal 26 with its lateral projections 85. In order to permit the terminal 28 to be brought to the position shown in Figures 3 and 4, in which the lower ends of the projections 45 are seated on the shoulder 58, longitudinal grooves or channels are provided in the. wall of the bore 48, the channels being complementary to the crosssectional aspect of the projections 45 and constructed and arranged to permit free sliding of the projections in the channels. By bringing the terminal to a position in which the projections i-5 register with the channels 5|, the terminal may be moved longitudinally into the bore 48 (see Figure 6), and when the lower ends of the projections 45 are at a level at or above the shoulder 58, the terminal 26 may be rotated, desirably 90, to bring the parts to the. position shown in Figures 3 and 4. Itwill be understood that in order to disconnect the terminal 26 from the sleeve 3| all that is necessary is to execute the described movements in reverse order. One, or two holes 52 are desirably provided, extending through the sleeve 3| at the upper ends of the '4 shoulder 50, to permit observation of the relative position of the terminal and the sleeve.

It will be understood that in order to connect (or disconnect) the terminal 26 and the sleeve 3|, the tube 38 and the funnel means l8 are moved upwardly out of the way. The connection between the sleeve 3| and terminal 26 having been made, and the parts of the apparatus assembled as in Figures 1 and 2, comminuted insulating material is introduced through the opening 24. The insulating material falls down between the tube 38 and the inside of the sheath l8, passing down between the splines 39, and accumulating at the bottom of the sheath, The tube 38 may be reciprocated, or the entire apparatus may be vibrated, or both, to tamp and compact the comminuted insulating material, and as the tamped compacted material accumulates, the tube 38 gradually assumes a higher and higher position, until the sheath I8 is filled to somewhere near the top, or to any desired extent.

A slight longitudinal tension on the resistor 25 is desirable to keep it centrally located in the sheath {8 and prevent undesired sagging. This tension may be secured by adjustment of the vertical position of the rod 32, and hence of the terminal 28. The tension on the resistor 25 in conjunction with the mode of engagement here shown between the tapering surfaces 48 and the right angled shoulder 58, whereby the shoulder bites slightly into the tapering surfaces, better keeps the terminal 26 from rotating with respect to the sleeve 3| when the parts are in the position shown in Figure 3, while at the same time not interfering with the disconnection of the terminal and the sleeve when the sheath-filling operation has been completed. The tapering surfaces M facilitate insertion of the terminal 26 into the sleeve 3|.

From the foregoing it will be apparent to those skilled in the art that the illustrated embodiment of the invention provides new and improved apparatus for use in the manufacture of electric heaters, and accordingly, accomplishes the principal object of the invention. On the other hand, it also will be obvious to those skilled in the art that the illustrated embodiment of the invention may be variously changed and modified, or features thereof, singly or collectively, embodied in other combinations than those illustrated, without departing from the spirit of the invention, or sacrificing all of the advantages thereof, and that accordingly, the disclosure herein is illustrative only, and the invention is not limited thereto.

I claim:

1. Apparatus for use in introducing comminuted insulating material endwise into a tubular sheath to embed a resistor disposed in said sheath, comprising: positioning means, connectable to terminal means fastened to. an end of said resistor, constructed and arranged to position said resistor spacedfrom theinside surface of said sheath; said positioning means and said terminal means being so constructed and arranged that they are connectable and disconnectable merely by relative movement of said means; and said positioning means being so constructed and arranged as to permit view of the position of said terminal means relatively to said positioning means.

2. Apparatus for use. in introducing comminuted insulating material into a tubular sheathto embed a resistor disposed in said sheath, comprising: positioning means, connectable to termichannels 5!, at approximately the level of the vnal means fastened to an end of said resistor,

constructed and arranged to position said resistor spaced from the inside surface of said sheath; and said positioning means and said terminal means being so constructed and arranged that they are connectable merely by longitudinal relative movement followed by rotative relative movement, and disconnectable merely by aforesaid movements in the reverse order.

3. Apparatus for use in introducing comminuted insulating material into a tubular sheath to embed a resistor disposed in said sheath, comprising: positioning means, connectable to terminal means fastened to an end of said resistor, constructed and arranged to position said resistor spaced from merely by longitudinal relative movement followed by rotative relative movement, and disconnectable merely by aforesaid movements in the positioning means being ments intersect.

4. A terminal for a resistor, for use in holding said resistor positioned in a tubular sheath while comminuted insulating material is introduced sheath, said terminal having circumferentially spaced lateral projections.

5. A terminal for a resistor, for use in holding said resistor positioned in a tubular sheath while comminuted insulating material is introduced endwise into said sheath, said terminal comprising a generally cylindrical shank having circumferentially spaced lateral projections.

6. A terminal for a resistor, for use in holding said resistor positioned in a tubular sheath while comminuted insulating material is introduced endwise into said sheath, said terminal having circumferentially spaced lateral projections of arcuate cross-sectional outline.

7. A terminal for a resistor, for use in holding said resistor positioned in a tubular sheath while comminuted insulating material is introduced endwise into said sheath, said terminal having a shank with circumferentially spaced lateral projections, said projections having outermost surfaces tapering longitudinally to a junction with the surface of said shank.

8. A terminal for a resistor, for use in holding said resistor positioned in a tubular sheath while comminuted insulating material is introduced endwise into said sheat said terminal having a shank with circumferentially spaced lateral projections of arcuate cross-section, said projections having outermost surfaces tapering longitudinally to a junction with the surface of said shank.

9. A terminal for a resistor, for use in holding said resistor positioned in a tubular sheath while comminuted insulating material is introduced endwise into said sheath, said terminal comprising a shank having circtunferentially spaced lateral projections integral with said shank.

10. A terminal for a resistor, for use in holding said resistor positioned in a tubular sheath while comminuted insulating material is introduced endwise into said sheath, said terminal comprising a shank having circumferentially spaced lateral projections formed by side pressing said ihank.

11. Apparatus for use in introducing comninuted insulating material endwise into a tubular sheath to embed a resistor disposed in said sheath, comprising: positioning means, connectable to terminal means fastened to an end of said resistor, said positioning means comprishaving an open bore at its lower end and having an enlarged bore spaced from its lower end and providing a shoulder at the junction of said bores, said open bore having circumferentially spaced longitudinal channels.

12. Apparatus for use in introducing comminuted insulating material endwise into a tubular sheath to embed a resistor disposed in said sheath, comprising: positioning means, connectable to terminal means fastened to an end of said resistor, said positioning means comprising a sleeve having an open bore at its lower end and having an enlarged bore spaced from its lower end and providing a shoulder at the junction of said bores, said open bore having circumferentially spaced longitudinal channels of arcuate cross-section.

13. Apparatus for use in introducing comminuted insulating material endwise into a tubular sheath to embed a resistor disposed in said sheath, comprising: positioning means, connectable to terminal means fastened to an end of said resistor, said positioning means comprising a sleeve having an open bore at its lower end and having an enlarged bore spaced from its lower end and providing a shoulder at the junction of said bores, said open bore having circumferentially spaced longitudinal channels, and an opening through a wall of said sleeve at the approximate level of said shoulder.

14. Apparatus for use in introducing comminuted insulating material into a tubular sheath to embed a resistor disposed in said sheath, comprising: positioning means, connectable to terminal means fastened to an end of said resistor,

ranged that they are connectable merely by longitudinal relative movement followed by rotative relative movement, and disconnectable merely by aforesaid movements in the reverse order, said positioning means comprising a sleeve having an open bore at its lower end and having an enlarged bore spaced from its lower end and providing a shoulder at the junction of said bores, said open bore having circumferentially spaced longitudinal channels, and said terminal means comprising a shank having circumferentially spaced lateral projections slidable in said channels and seatable on said shoulder.

CHARLES W. CAPPELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,987,915 Smith Jan. 5, 1935 2,375,058 Wiegand May 1, 1945 2,376,840 Wiegand May 22, 1945 2,413,477 Wiegand Dec. 31, 1946 FOREIGN PATENTS Number Country Date 43,218 Netherlands May 16, 1938 

